Project Summary: The detection and enumeration of circulating tumor cells (CTCs) has the potential to become a very powerful tool in cancer diagnosis and treatment. However, current technologies for CTC detection are not yet established in routine clinical practice. One reason is that CTCs are present in blood at an extremely low concentration of one in 10 million white blood cells. Existing technologies lack the sensitivity and/or specificity required for reliable detection of these rare CTCs. Another reason is that current technologies do not offer information about the molecular status of CTCs, which can be used to select appropriate targeted therapy and monitor therapy response. The overall goal of this proposal is to develop an automated system called CTCscope for detection and molecular phenotyping of circulating tumor cells (CTCs) in blood. This automated system is based on the successful development of ACD's RNAscope technology and prototype CTCscopesystem, both of which are supported in part by a SBIR Phase II grant R44CA122444. Our aim in this proposal is to develop and validate the automated CTCscope system for sensitive detection, accurate enumeration, and molecular characterization of CTCs. The long term goal of this effort is to leverage CTCscope to develop a suite of high value cancer diagnostic products. These products would satisfy many significant unmet needs in cancer management, especially in the areas of early detection, therapy selection and guidance, and recurrence monitoring. With the support of the SBIR phase II grant, we have successfully developed the RNAscopeassay capable of in situ multiplex detection and quantification of RNA markers with single molecule sensitivity and exquisite specificity. We have also developed a manual prototype system for CTC detection and analysis. The manual system includes three components: 1) CTC preservation: CTCs are preserved and RNA stabilized in the blood sample; 2) CTC labeling: CTCs are labeled for multiple RNA markers in situ by the RNAscopeassay; and 3) CTC detection and analysis: CTCs are detected, enumerated and characterized based on RNA marker signals observed under the fluorescent microscope. Using this system, we have demonstrated highly specific detection of circulating tumor cells and characterized their EGFR expression status in breast cancer patients. These data demonstrated that CTCscope has several unique capabilities which could potentially offer significant advantages over existing CTC detection methods. In this proposal, we will extend our current work to develop and validate an automated CTCscope system for reliable detection and enumeration of CTCs, and for quantitative analysis of RNA markers reflective of CTCs' molecular phenotype. In addition, as part of the CTCscope system validation, the HER2 and EGFR status of the CTCs and their concordance/discordance with their status in primary tumor will be determined. The specific aims include: 1) Develop an automated CTCscope system for CTC detection and molecular characterization; 2) Validate CTCscope by comparing its performance with the CellSearch(R) system using blood samples from ~230 metastatic breast cancer patients; and 3) Determine HER2 and EGFR status on CTCs and compare their status on primary tumors. The specific outcomes of this research will include an automated CTCscope platform that is successfully developed and validated, enabling a suite of high value diagnostic products to be developed for greatly improved cancer management. This research will also lay the foundation for a valuable diagnostic product that can guide targeted therapy selection and monitor therapy response for metastatic breast cancer patients. With the CTCscope platform successfully developed and validated, a suite of high value diagnostic products can be developed for greatly improved cancer management.